About:

• The United States Government has made it clear that the delivery of the five S-400 systems is considered a “significant transaction” under its Countering America’s Adversaries Through Sanctions Act (CAATSA) of 2017, which could trigger sanctions against Indian officials and the Government.
  
  
• The CAATSA is designed to ensure that no country is able to increase military engagement with Iran, North Korea and Russia without facing deterrent punitive action from the U.S.
  
  
• The sanctions are unilateral, and not part of any United Nations decision, and therefore no country is bound to accept them.
  
  
• Section 231 says the President shall impose no fewer than five different sanctions on any Government that enters into a significant defence or intelligence deal with the Russian Government.
  
  
• Section 235 lists 12 options, including stopping credit lines from U.S. and international banks such as the IMF, blocking sales of licensed goods and technology, banning banks, manufacturers and suppliers, property transactions and even financial and visa sanctions on specific officials.
  
  
• However, the law empowers the President to waive sanctions or delay them if he/she certifies that the deal is not a threat to the U.S. and allies, that waiver of sanctions is in the U.S.’s “vital national security interests” or that the country being sanctioned promises to reduce its future dependence on the “adversary country”.